The telecommunication industry has undergone dramatic evolutionary changes over the past twenty years. In short, it has gone from a system that primarily provided simple party-to-party voice communication using rotary dial telephones over wireline connections to a complex inter-network system that provides a plethora of communications over wireline/optical/wireless/satellite connections. For example, today, the subject medium of a communication may be voice, data, video, multi-media or facsimile and such communication may be received/transmitted by digital telephones, analog telephones, cellular telephones, computers, facsimile machines, etc.
This evolution has been so dramatic that it has spawned a plurality of new technologies and caused evolutionary changes within these new technologies. For example, cellular communications has undergone dramatic evolutionary changes since its initial conception in 1947 by AT&T. The first major evolutionary change occurred in the 1970's when the technology was developed to make call-hand off commercially viable. Call hand-off is the capability of maintaining communications between a cellular phone and another telephone as the cellular phone moves from an area served by a first base station to an area served by a second base station.
Advanced Mobile Phone Service (AMPS) became a commercial success for sophisticated consumers as a result of the call hand-off technology. As the demand for cellular service grew, new systems, having new over-the-air protocols and increased capacity, were created. For example, Time Division Multiple Access (TDMA) and Global System for Mobile Communications (GSM) were developed and commercialized in the 1980's and early 1990's. Now, with the ever increasing processing power of integrated circuits, digital communication systems are being developed, such as Code Division Multiple Access (CDMA), Digital AMPS, and Personal Communications Service (PCS).
In addition to the dramatic technical changes, the number of services and the ease of use of the services has dramatically changed as well. For example, a wireless telephone user may receive facsimile transmissions, use call forwarding, use caller identification, and a plurality of other features. And each of these features can be done more conveniently than in the past.
As can be understood from this brief discussion, the wireless communications industry has dramatically changed and evolved. One drawback to the dramatic wireless telecommunication advances is that the different systems are not compatible with each other. For example, an operator of an AMPS wireless telephone cannot access a TDMA, CDMA or any system other than an AMPS system. The operator of the AMPS phone, however, may communicate with an operator of a TDMA phone, but the communication must be routed through the Public Switched Telephone Network (PSTN) for protocol conversion.
In general, to allow a wireless user of one type of over the air interface (i.e., first communication protocol) to communicate with another wireless user of a different over the air interface (i.e., second communication protocol), the communication must be routed to PSTN. The PSTN then does a protocol conversion from one over the air interface to the other. This is done by converting the incoming call, which has a first over-the-air protocol, to the voice domain. Then the PSTN converts the voice domain information into the over-the-air protocol of the receiving communication device. This conversion process continues as long as the two communication devices are engaged in a communication.
This scenario occurs even when both users are in the same geographic area. For example, assume a remote geographic location is linked to the PSTN via satellite and the remote location offers fixed wireless access, wireline services, and wireless services such as TDMA, CDMA, GSM, etc. For a communication between a fixed wireless device and any other communication device, the communication must be routed to the PSTN via the satellite link for conversion. The same is true for wireless devices that use different over the air interfaces. Thus, even though the communicating parties are in relatively close physical proximity, the communication must be routed a significant distance to support the inter-protocol communication. As one would expect, this adds to communication traffic and reduces the efficiency of the overall telecommunications network.
Therefore, a need exists for a method and apparatus that allows for conversion of telecommunication protocols in a manner that permits communication between devices that utilize different protocols and reduces communication overhead over the PSTN.